helps finding which partial to look at in rails4

renderer.rb

if Rails.env.development?
  module My
    module PartialRenderer
      def render(context, options, block)
        msg = "rendering '#{options[:partial]}' with locals '#{(options[:locals] || {}).keys}'"
        "<!-- start #{msg}-->\n#{super(context, options, block)}\n<!-- end #{msg}-->\n".html_safe
      end
    end
  end

  ActionView::PartialRenderer.prepend(My::PartialRenderer)
end